Zipp 404 Wheel Question

My front Zipp 404 hub rattles a bit when I ride. Any ideas why?

From zipp.com FAQ:

My dust caps rattle on my Zipp hubs how can I fix this?
The carbon dust caps are held in place on the axle cap by a couple of rubber grommets. The reason they are making a racket is that this grommet has come unseated and is allowing the cap to move freely. To fix find a couple of 5 mm allen keys and insert one into each axle cap on the hub (where the quick release runs through). Work these wrenches against each other (standard right hand thread) to loosen one end cap. Remove the axle and reseat the grommet against the back of the dust cap. You may even want to put down a bead of super glue or quick set epoxy behind the grommet to ensure that it does not move again. Allow glue to dry fully, reinstall axle, torque end caps to 55 in lb (88 in lb rear) and go ride.

Thanks.